nondescript/examples/bf.nds

var main = proc() {
  // source
  var src = ">++++++++++[<++++++++++>-]<->>>>>+++[>+++>+++<<-]<<<<+<[>[>+>+<<-]>>[-<<+>>]++++>+<[-<->]<[[-]>>-<<]>>[[-]<<+>>]<<[[-]>>>>>>[[-]<++++++++++<->>]<-[>+>+<<-]>[<+>-]+>[[-]<->]<<<<<<<<<->>]<[>+>+<<-]>>[-<<+>>]+>+<[-<->]<[[-]>>-<<]>>[[-]<<+>>]<<<[>>+>+<<<-]>>>[-<<<+>>>]++>+<[-<->]<[[-]>>-<<]>>[[-]<<+>>]<<[>+<[-]]<[>>+<<[-]]>>[<<+>>[-]]<<<[>>+>+<<<-]>>>[-<<<+>>>]++++>+<[-<->]<[[-]>>-<<]>>[[-]<<+>>]<<[>+<[-]]<[>>+<<[-]]>>[<<+>>[-]]<<[[-]>>>++++++++[>>++++++<<-]>[<++++++++[>++++++<-]>.<++++++++[>------<-]>[<<+>>-]]>.<<++++++++[>>------<<-]<[->>+<<]<++++++++[<++++>-]<.>+++++++[>+++++++++<-]>+++.<+++++[>+++++++++<-]>.+++++..--------.-------.++++++++++++++>>[>>>+>+<<<<-]>>>>[-<<<<+>>>>]>+<[-<->]<[[-]>>-<<]>>[[-]<<+>>]<<<<[>>>+>+<<<<-]>>>>[-<<<<+>>>>]+>+<[-<->]<[[-]>>-<<]>>[[-]<<+>>]<<<[>>+<<[-]]>[>+<[-]]++>>+<[-<->]<[[-]>>-<<]>>[[-]<<+>>]<+<[[-]>-<]>[<<<<<<<.>>>>>>>[-]]<<<<<<<<<.>>----.---------.<<.>>----.+++..+++++++++++++.[-]<<[-]]<[>+>+<<-]>>[-<<+>>]+>+<[-<->]<[[-]>>-<<]>>[[-]<<+>>]<<<[>>+>+<<<-]>>>[-<<<+>>>]++++>+<[-<->]<[[-]>>-<<]>>[[-]<<+>>]<<[>+<[-]]<[>>+<<[-]]>>[<<+>>[-]]<<[[-]>++++++++[<++++>-]<.>++++++++++[>+++++++++++<-]>+.-.<<.>>++++++.------------.---.<<.>++++++[>+++<-]>.<++++++[>----<-]>++.+++++++++++..[-]<<[-]++++++++++.[-]]<[>+>+<<-]>>[-<<+>>]+++>+<[-<->]<[[-]>>-<<]>>[[-]<<+>>]<<[[-]++++++++++. >+++++++++[>+++++++++<-]>+++.+++++++++++++.++++++++++.------.<++++++++[>>++++<<-]>>.<++++++++++.-.---------.>.<-.+++++++++++.++++++++.---------.>.<-------------.+++++++++++++.----------.>.<++++++++++++.---------------.<+++[>++++++<-]>..>.<----------.+++++++++++.>.<<+++[>------<-]>-.+++++++++++++++++.---.++++++.-------.----------.[-]>[-]<<<.[-]]<[>+>+<<-]>>[-<<+>>]++++>+<[-<->]<[[-]>>-<<]>>[[-]<<+>>]<<[[-]++++++++++.[-]<[-]>]<+<]";
  var pos = 0;
  var len = #src;
  var chr;
  var depth = 0;

  // input
  var input = "";
  var inppos = 0;

  // tape
  var tape = @[];
  var ptr = 0;
  var ptrmax = 30000 - 1;

  var i = 0;
  while (i < ptrmax) {
    tape[i] = 0;
    i = i + 1;
  };

  { @mainloop
    while (pos < len) {
      chr = src[pos];

      if (chr == "<")
        if (ptr > 0)
          ptr = ptr - 1
        else
          ptr = ptrmax
      ;

      if (chr == ">")
        if (ptr < ptrmax)
          ptr = ptr + 1
        else
          ptr = 0
      ;

      if (chr == "+")
        if (tape[ptr] < 255)
          tape[ptr] = tape[ptr] + 1
        else
          tape[ptr] = 0
      ;

      if (chr == "-")
        if (tape[ptr] > 0)
          tape[ptr] = tape[ptr] - 1
        else
          tape[ptr] = 255
      ;

      if (chr == ".")
        write(char(tape[ptr]))
      ;

      if (chr == ",") {
        tape[ptr] = byte(input[inppos]);
        inppos = inppos + 1;
      };

      if (chr == "[") {
        if (tape[ptr] == 0) {
          depth = depth + 1;
          while (depth > 0) {
            pos = pos + 1;
            chr = src[pos];
            depth = depth + 
              if (chr == "[")
                1
              else if (chr == "]")
                -1
              else
                0
            ;
          };
        };
      };

      if (chr == "]") {
        if (tape[ptr] != 0) {
          depth = depth + 1;
          while (depth > 0) {
            pos = pos - 1;
            chr = src[pos];
            depth = depth +
              if (chr == "]")
                1
              else if (chr == "[")
                -1
              else
                0
            ;
          };
        };
      };
        
      pos = pos + 1;
    };
  };

};

main();